package com.miaoshaproject.practise;

import java.text.SimpleDateFormat;
import java.util.Random;

public class ThreadLocalExample implements Runnable{
    // SimpleDateFormat 不是线程安全的，每个线程都有自己独立的副本
    private  static final ThreadLocal<SimpleDateFormat> formatter = new ThreadLocal<SimpleDateFormat>(){
        public  void main(String[] args) throws InterruptedException { // static JDK8.0不支持
            ThreadLocalExample obj = new ThreadLocalExample();
            for (int i = 0; i < 10; i++) {
                Thread t = new Thread(obj,"" + i);
                Thread.sleep(new Random().nextInt(1000));
                t.start();

            }


        }

    };





    @Override
    public void run() {
        System.out.println("Thread Name= "+Thread.currentThread().getName()+" default Formatter = "+formatter.get().toPattern());
        try {
            Thread.sleep(new Random().nextInt(1000));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //formatter pattern is changed here by thread, but it won't reflect to other threads
        formatter.set(new SimpleDateFormat());

        System.out.println("Thread Name= "+Thread.currentThread().getName()+" formatter = "+formatter.get().toPattern());
}
}
